On Saturday, at the T-Mobile Arena, some 200 metres from Sin City's infamous strip, Wallin will lace up his gloves and face the undefeated, former unified heavyweight champion of the world, Tyson Fury.

It is the culmination of 13 years in the ring and the product of endless chats with his father, who obsessed over Muhammad Ali in their Swedish home.

"My father passed away in May. He had a heart attack, it was very unexpected," Wallin told BBC Sport.

"He was here in America with me in April and then went back home and unfortunately that happened. He was 68."

'He will be there in spirit, no doubt'

Wallin says his father only allowed him to start boxing aged 15

Wallin's voice is strong and steady as he explains the loss of his father. He has grieved and, by his own admission, found welcome distraction in focusing on what will be the biggest night of his sporting life.

Despite standing at 6ft 5in, boasting a tricky southpaw stance and being unbeaten in 20 contests, the 28-year-old's threat to Fury has been written off, talked down and scoffed at by fans, pundits and fighters alike.

So too were James 'Buster' Douglas' chances as he prepared to face Mike Tyson - the man Fury is named after - in 1990.

Just 23 days before the world title bout in Tokyo, Douglas lost his 46-year-old mother Lula Pearl to a stroke. He buried her before flying to Japan and after landing the biggest shock in boxing history, told the media he had found a win "because of my mother, God bless her heart".

Grief, seemingly, can galvanise in the fight game.

Wallin continues: "It is on my mind, of course. It was always a dream of his to have me fight in Vegas one day. I just wish he could be there but it gives me a lot of motivation. We talked about this beforehand. He always said if something were to happen to him I should keep going and keep fighting.

"The thing is, me and my father had a really good relationship. He was a guy who talked a lot about feelings. He knew I loved him and I knew he loved me. He will be there in spirit for sure, no doubt."

Fighting AJ and a Vegas chance

Wallin hopes beating Fury will prove "life changing"

Wallin followed his fighting father and brother to the gym in their home city of Sundsvall on Sweden's east coast. He would watch but was not allowed to enter the ring until eventually being granted permission by his parents aged 15.

The tall, skinny, teenage footballer "fell in love" with boxing. He was converted to the rigours and loneliness of individual sport and felt comfortable knowing he need not rely on team-mates in pursuing success. At home, his father would preach the fundamentals of the sweet science.

"I remember the smell of the gym as a kid," he said. "My dad believed in a good jab and good basics. He was always talking about Muhammad Ali and his jab. Both Ali and my dad are my heroes, for sure.

"In Sweden we have light-contact boxing before you can have a real fight. I had three of these. In my first real fight I was surprised as the bell rang and the guy was there trying to take my head off. I pulled it together and that was just a brief moment of doubt I had."

There will be no room for doubt when the bell rings against Fury in a bout which will be broadcast on BBC Radio 5 Live at around 04:00 BST on Sunday in the UK.

Wallin, who has prepared by training twice a day at a New York gym closed off to the public, insists stage fright has long left his system.

Two contests with former world champion Anthony Joshua during their amateur days helped sharpen his game, as did countless rounds the pair shared sparring as professionals.

"Fighting him in the amateurs was special," Wallin recalls. "He was big, powerful and I was a little smaller but we were both very raw. They were competitive fights but I lost decisions. You learn a lot from those and who could have known that he would become world champion? I had no idea about that when we fought."

Wallin had his first pro fight in 2013, aged 22, four months before Joshua did the same. So began life on the road, with spells living in Denmark and Germany before relocating to the US.

His endeavour will be rewarded with the biggest purse of his career in facing Fury, money he may invest in customising tools to fit his huge frame for his latest hobby.

"I started playing golf last year," he says. "My handicap is only 25, so not so good. I sometimes wonder if I should have longer clubs but the guy that sold them to me says it doesn't matter so I don't really know.

"I will make a good purse out of this fight but if I win it will be really life-changing so I am trying to do everything I can to do that."

The mansion and Rolls-Royce splashed across the social media pages of Andy Ruiz Jr following his stunning defeat of Joshua show the rewards a shock for the ages can provide.

But Wallin, who will be flanked by his two brothers, mother and around 20 friends for his first trip to Las Vegas, has more than money on his mind.

"My father taught me good lessons that I have to put everything in and that I will only get this chance once," he adds.

Asked if he feels tears may follow should he land a colossal shock, he simply replies: "Probably. You just never know when those moments will come."